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Ice Out Dates

Ice-out Dates From 1901

The Nugget has recorded the annual departure of ice from Lake Nipissing since 1901. The earliest that all of Lake Nipissing (85,870 ha) was reported clear of ice was April 3, 1945. The latest was May 19, 1926.

Lake Nipissing Ice Free Dates Statistics

Dates were converted to days after March 31. (For example May 6 is 36 days after March 31.)

The overall average date is 28.1 days after March 31, thus April 28.
The median (middle value of ranked dates) is also April 28.

The standard deviation is plus or minus 8.9 (or 9) days. The "average range" is by definition the statistical range between +1 and -1 standard deviations and contains 68% of all dates. The average range lies between April 19 and May 7.

Statistically, the "best guesses" for ice-off dates are between April 19 and May 7, with April 28 in the middle.

Since the year 2000, there have been 4 ice-outs after April 28 and 9 before, and 1 actually on April 28. Despite the very cool and late spring in 2014, there is a trend towards earlier than average ice-out dates. The average date has shifted slightly earlier from 28.4 to 28.1 days after March 31.